In recent times there have been increasingly widespread uses of energy beams, e.g. electron beams, ion beams, plasma beams or laser beams in the field of machining, processing and measurement arts.
In these applications it has become apparent that it is desirable to pulse beamed energy radiation and also to control the energy flow being radiated onto a workpiece precisely, depending upon the particular operation to be performed thereon. While various control devices have hitherto been proposed and put into practical use for a beam gun and a power supply therefor, these devices have been found to be either highly sophisticated in structure or unsatisfactory in precisely controlling the energy flow onto the workpiece in a particular mode as desired.